People nowadays are exposed to long working hours, various physical and mental stress environment, or the like; and many of those people complain physical symptoms such as loss of appetite, sleep disruption, dizziness, or cold sweat, or mental symptoms such as a hatred or distrust of other people, emotional instability, state of being irritated, or depressed mood, even though no abnormalities are found when examinations such as physical checkup. Symptoms associated with such unidentified complaints are often diagnosed as dysautonomia. In the present circumstances, such a dysautonomia is usually treated with a drug therapy such as a minor tranquilizer or hormonal agent, treatment by diet, lifestyle changes for the better such as exercise, or the like.
It has been known that autonomic disorders including dysautonomia described above are induced by excessive loads of stress. In the autonomic disorder, disturbance in the balance between the sympathetic nerve and the parasympathetic nerve (the balance of the autonomic nerve), lowered activity of the autonomic nerve, or the like is observed. The disturbance in the balance of the autonomic nerve means a state with increased activity of the sympathetic nerve or a state with increased activity of the parasympathetic nerve. Further, it has been known that the capacity to deal with stress is decreased by a lowered activity of the autonomic nerve. For instance, because functions of the gastrointestinal tract are mainly innervated by the parasympathetic nerve, prolonged tonus of the sympathetic nerve due to loads of stress suppresses the function of the gastrointestinal tract, resulting in gastrointestinal disorders such as loss of appetite or constipation. In addition, it is thought that when the parasympathetic nerve does not function well because of loads of stress and the activity of the sympathetic nerve remains elevated, sleep disruption is brought about.
While there is, as described above, a close relationship between stresses and autonomic disorders, there are also autonomic disorders that are not caused by loads of stress. In addition, the load of stress does not necessarily bring about the autonomic disorder and may in some cases induce other physical symptoms.
As one of the proteins called stress proteins, there are heat shock proteins (hereinafter, referred to as HSPs). HSPs are proteins with a molecular weight of about several tens of thousands to one hundred fifty thousand and are divided into several families on the basis of the molecular weight thereof (HSP10, HSP27, HSP40, HSP60, HSP70, HSP90, HSP110, and the like). HSPs are a group of proteins that are induced within cells when living organisms are put under physical, chemical, physiological, or mental stress. To be specific, HSPs have a role of protecting cells, exhibiting increased expression when living organism are exposed to various conditions including heat, bacterial infection, inflammation, reactive oxygen species, ultraviolet rays, starvation, and hypoxia. In addition, HSPs also have functions as molecular chaperones including control of protein folding and inhibition of aggregation of abnormal proteins.
Among HSPs, HSP70 has been actively studied in particular, and has been reported to be constitutively expressed in many internal organs including the gastrointestinal tract and skin. Recently, HSP70's antiapoptotic action and anti-inflammatory action have been recognized and HSP70's cell protection effect against various stresses has been reported (Non Patent Literatures 1 to 4). Due to this, studies have come to be conducted, attempting to apply materials with HSP70 inducing activities in pharmaceuticals, cosmetics, or the like. When it comes to natural product-derived materials with the HSP70 inducing activity, paeoniflorin which is a major component of Paeoniae radix has been reported (Non Patent Literature 5).
Asparagus is a vegetable that is cultivated and harvested in various regions including Hokkaido in Japan. It has been found that asparagus has various biological activities. Patent Literature 1 describes that an asparagus stem extract has preventive and restorative effects for various types of fatigue (such as physical fatigue or fatigue due to mental stress). Further, Patent Literature 2 describes that an asparagus stem extract has an effect of improving brain functions. Further, Patent Literature 3 describes that an asparagus pseudo leaf extract has an effect of controlling the autonomic nerve.